PITTSBURGH — Pittsburgh police say a woman has been seriously injured after being struck by three vehicles, including a box truck which left the scene after running her over. The incident happened about 7 a.m. today in the Strip District. Police at the scene say the woman was hit by a vehicle whose driver remained at the scene before she was also run over by the box truck which drove away. The driver of a third vehicle tried to stop before hitting the woman but, instead, wound up pinning her to the ground. Police say that driver also stopped at the scene. The woman’s name and condition were not immediately available.